I think it would be. Honestly, invert the main lifting elements and have them come out the side and you have something pretty close to the recent Vendee Globe boats. Except the Vendee Globe boats were intended to heal and then get lift but not fully foil. That pictured (old is new again!) concept leaves the boat more upright and provides a wider more stable foiling platform in comparison so it would probably course race a little better than a Vendee Globe boat. Conceptually, the hull could be more needle-like and the outer structure of the foils system could host some minor buoyancy detail that would help the boat remain upright when at a stand still....kinda like a monohull being a trimaran at exceptionally low speeds. More stable than a Moth (when not significantly moving) but with similar ingrained stability provided by the 'L'/(canted)'V' shapes that were derived in the catamaran America's Cups.

Honestly, I think we'll see the lines between monohull/multihull really blurred with the next development steps of foiling as the foils become more and more efficient. In 10 years, we'll probably look at boats classifications more as one of three classifications instead of two - monohull/multihull/foiler. Foiler designs right now are a lot of different boat classifications applying foils in more and more similar ways....they'll eventually converge into a single fast and stable layout, IMO, and become unified as one thing when the designs converge on a stable and operationally convenient configuration. The design task looks complicated because of all of the variations out there right now - but it's not. You need stability at low and high speeds while reducing the appendages in the water so your drag is low at high speed. A three point foiling system (Helllllooooo Hobie Trifoiler) makes sense here with a low speed "landing gear" to keep the boat stable when the foils can't do it.

You can also draw some really distinct parallels to aeronautical design in it's infancy...lots of really weird configurations before the bi-planes (catamarans) got it working and became the semi-standard for a short while. Other things flew but they were very complex. As wing shapes, drive system efficiency, and manufacturing technology matured, the biplane designs evolved into a single wing three lifting point configuration that became the universal standard in all but the most extreme cases.

So my bottom line, while we may get all emotional about multi-hull / monohull, in a short time, this foiling thing won't really be either one of them anymore (and I can have my a-cat class back).